This invention relates generally to a new and improved coupling which is utilized to interconnect a pair of conduits. More specifically, the invention relates to a coupling which interrupts fluid communication between the conduits upon exposure of the coupling to excessive heat.
A known coupling having a socket valve which is closed to interrupt fluid communication between a pair of conduits upon exposure of the coupling to excessive heat, is disclosed in U.S. Pat. No. 3,245,423. The coupling disclosed in this patent includes a plug assembly having a valve actuator member. The valve actuator member includes a cylindrical metal sleeve which is soldered to a metal plug body. A bridge portion extends from one end of the sleeve and engages the socket valve to hold the valve in the open condition.
Upon exposure of the coupling to excessive heat, the solder securing the sleeve to the plug body fuses. This allows the sleeve to move axially into the plug body under the influence of force applied against the bridge portion by the socket valve. As the sleeve and bridge portion move axially into the plug body, the socket valve closes to block fluid flow through the coupling.
The cost of assembling the coupling disclosed in U.S. Pat. No. 3,245,423 is increased by soldering the sleeve to the metal plug body. In addition, the forming of the one piece metal bridge portion and sleeve increases the cost of making the coupling.